Feb 2017
Guide to Car Batteries

Few things are as annoying as settling into your car, ready to get home after a long day of work, only to realize your car battery is dead. Here’s a quick guide to car batteries. Looking for 'auto batteries near me', come visit A Autocare for great batery service.

Auto batteries

What is an auto battery?

An automotive battery is a rechargeable battery that supplies electrical energy to a vehicle.

Image of DieHard battery. Red post (+), Black post (-)


What does a car battery do?

The main purpose of a car battery is to the start the car. When the engine is not running, all power comes from the battery. Once the engine is running, electrical energy is supplied by the alternator.

Image of auto electrical system


What is an alternator

An alternator is a generator, which converts mechanical energy into electric power. Whenever your engine is running, the alternator charges the battery and supplies additional electric power, ie radio, lights, spark plugs, etc.

Image of alternator.

With the engine not running, the battery will read 12.6 volts at full charge. With the engine running the battery will read 13.7 – 14.7 volts, since the alternator is producing power & recharging the battery.


Where is my car battery located?

On most cars, the battery is located in the front of the car, engine bay. In many BMW’s, the battery is in the trunk. In some newer cars, I’ve seen the battery underneath the seat. Check your owner’s manual if unsure.

Image of battery location in Audi


How long will a car battery last?

Most batteries will have a stamp on them, which tells you the month and year the battery was made so you’ll have an idea of when it needs to be replaced. Car and truck batteries typically last three to six years.

You will likely have to replace the car battery once or twice throughout the life of your vehicle, either because it gets old or worn out from repeated charging and discharging.

Image of battery chart showing cold cranking amps & warranty info for serval battery manufacturerers.


What are signs of a bad or dead auto battery?

  • If the battery shows signs of acid leaking or corrosion buildup on the terminals it can be an indication that the battery is starting to fail.

Image of battery corrosion buildup

  • With a multimeter you can check the voltage of the battery with the engine off. If lower then 11.8 volts the battery could be bad or failing.
  • If you’re lucky your car battery will show signs of dying (electrical items going on and off, motor cranking slowly), but most will be an experience of one day it just wont start. This will require you to probably get a jump start to get home or to a auto parts store.


How to purchase car batteries

Don’t buy batteries that have been on the shelf longer than six months. The date stamp code gives you the battery’s born date.


Is my car battery under warranty?

All batteries are covered under their own manufacturer’s warranty. Car battery prices will usually be higher with longer free replacement period.

A battery’s warranty is measured in two figures: the free replacement period and the prorated period–which allows only partial reimbursement.


More info

In the blogs I will discuss how to check car batteries, car battery cost, car battery sales, car battery chargers, cheap car batteries, etc.